This proposal describes a five-year multidisciplinary career development program, which will enable the Principal Investigator, an MRI and cardiovascular radiologist, to become a productive independent patient-oriented investigator in cardiovascular imaging. Cardiac arrhythmias, frequent in patients with ischemic heart disease, may lead to sudden cardiac arrest, which claims over 450 000 lives per year in the US. They can be prevented by medication, which has a high failure rate and frequent toxicity, or corrected by an Implantable Cardioverter Defibrillator (ICD). 150 000 ICDs were implanted in the US in 2003, number that is growing every year. ICDs have a significant impact on quality of life, as the discharge from an ICD is described as similar to being kicked in the chest by a horse. Radiofrequency ablation under guidance of cardiac electrical mapping, a therapy rapidly growing in importance and popularity, can be used to cure non-life threatening arrhythmias, and minimize or even eliminate the painful discharges experienced by patients with prospective ICDs. The focus of this research is the development and application of novel magnetic resonance imaging (MRI) techniques to improve cardiac ablation therapy. The principal aims are: (1) to develop novel techniques to perform high resolution MRI to assess myocardial damage, (2) to show that MRI can predict the distribution of abnormalities on cardiac electrical mapping due to myocardial damage, making cardiac ablation therapy more efficient, and (3) use MRI to characterize the distribution and progression of cardiac ablation lesions, in order to predict failure of therapy and complications. The career development program has two major components: a technical component, and a translational component. The technical component involves the development of the imaging techniques, to be performed under the mentorship of a leading scientist in biomedical imaging. The translational component involves a didactic component, provided by the University of Michigan's Training Program in Clinical Research, which leads to a Masters degree in Clinical Research Design and Statistical Analysis, and a clinical research component, that involves the testing of the imaging techniques in clinical studies in cardiac electrophysiology, under the mentorship of an internationally recognized pioneer in the field. The program would take place in an environment which has a long tradition of support for junior patient- oriented investigators, and which is at the cutting edge of both medical imaging and cardiac electrophysiology, with extensive clinical, educational and research resources. Relevance: MRI has the potential to make cardiac ablation therapy more efficient and to predict failure and complications of this therapy. This can dramatically improve the lives of people with arrhythmias.